How do you have your idle screws (front and back) set? You should have a perfect square on the primary transfer slot. Once that is set, adjust the air mixture screws, it you need a little more idle speed open the secondaries a bit (with the screw you have to get at from the bottom). Does your idle mixture screws have any effect on the idle? If not you probably have your throttle plates open too far (idle screw). If you can't get a decent clean idle, you may have no choice but, to drill the primary throttle plates. Sometimes that is the only (easy) way. You don't have screw in air bleeds right?